Refrigerating apparatus

ABSTRACT

An apparatus for refrigerating, either freezing or chilling, articles and particularly food items comprising a chamber having an entrance and an exit, a conveyor in the chamber for moving the articles in a path from the entrance to the exit, means for introducing a fluid cryogen and particularly one in the nature of liquid carbon dioxide which at lower pressures such as atmospheric pressure exists in the form of solid particles and gas, means for withdrawing spent cryogen fluid after it has chilled the articles and an elongated flow confining baffle in the chamber adjacent to the area of withdrawing and adjacent to the conveyor for increasing the gas velocity adjacent to the baffle while simultaneously restricting the withdrawal of the spent gas. The disclosure also includes improved gas balance means including additional gas flow retarding devices and devices for achieving gas recirculation prior to the exhausting of the spent gas from the chamber.

ilnited States Patent [19] Wagner Dec. 24, 1974 [22] Filed:

[ REFRIGERATING APPARATUS [75] Inventor: Richard C. Wagner, Darien, Ill.

[73] Assignee: Hollymatic Corporation, Park Forest, ill.

Mar. 8, 1973 [21] Appl. No.: 339,395

Related U.S. ApplicationData [63] Continuation-impart of Ser. No. 264,133, June 19, i972, Pat. No. 3,824,806.

[52] US. Cl 62/266, 62/374, 62/380 Primary Examiner-Meyer Perlin Assistant ExaminerRonald C. Capossela Attorney, Agent, or Firm-Hofgren, Wegner, Allen, Stellman & McCord [57] ABSTRACT 1 An apparatus for refrigerating, either freezing or chilling, articles and particularly food items comprising a chamber having an entrance and an exit, a conveyor in the chamber for moving the articles in a path from the entrance to the exit, means for introducing a fluid cryogen and particularly one in the nature of liquid carbon dioxide which at lower pressures such as atmospheric pressure exists in the form of solid particles and gas, means for withdrawing spent cryogen fluid after it has chilled the articles and an elongated flow confining baffle in the chamber adjacent to the area of withdrawing and adjacent to the conveyor for increasing the gas velocity adjacent to the baffle while simultaneously'restricting the withdrawal of the spent gas. The disclosure also includes improved gas balance means including additional gas flow retarding devices and devices for achieving gas recirculation prior to the exhausting of the spentgas from the chamber.

5 Claims, 7 Drawing Figures REFRIGERATING APPARATUS CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my copending application Ser. No. 264,133, filed June 19, 1972 now US. Pat. No. 3,824,806.

BACKGROUND OF THE INVENTION sulated chamber having improved gas recirculation and 2 gas balance means for achieving rapid refrigerating of I the articles with the fluid cryogen before expelling spent cryogen from the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 6 is an enlarged sectional view partially in side elevation and partially broken away taken substantially along line-66 of FIG. 1

FIG. 7 is an enlarged sectional view partially in side elevation and partially broken away taken substantially along line 77 of FIG. 1.

- DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of this invention as disclosed andclaimed herein has many features'that aredisclosed and claimed in my above application'of which this is a continuation-impart.

In the embodiment of the apparatus 10 disclosed in the accompanying drawings there is provided an elongated thermally insulated chamber 11 comprising a series of end-to-end subchambers 12 each with thermally insulated walls as shown in FIG. 2 and insulated hinged lids 13. The subchambers- 12 are releasably latched together in end-to-end relationship by latches 14 while the lids 13 are normally latched closed by latches 15. 7

As shown in FIG. 5 each lid 13 can be raised for servicing and cleaning the interior of the chamber or tunnel 11 by means of air cylinder and piston structures 16 positioned along one side of the chamber or tunnel 11.

larly passes over a driven roller 22 that is motor driven in the customary manner by a motor drive identified generally at 23 in FIG. 1. This type of endless open metal conveyor and drive is disclosed in my prior US. Pat. No- 3,580,000 which is assigned to the same assignee as the present application.

The liquid cryogen used in the illustrated embodiment is liquid carbon dioxide and is supplied to the apparatus 10 from a source (not shown) through a pipe 24 that extends into the insulation 25 leading to a mass of insulation 26 in which is located a gas recirculation blower 27 driven by an external electric motor 28.

The pipe 24 is adapted to have liquid carbon dioxide under pressure circulated continuously in that the pipe includes an inlet 29, a loop 30 within the insulation 26 and an outlet 31 leading back'tothe source of liquid cryogen. By keeping the liquid circulating continuously there is less chance-of the carbon dioxide setting up in the pipe 24 to a solid and thereby stopping the flow.

In order to supply the fluid cryogen to the apparatus there is provided a main on-off control valve 32 which is of a ball valve type operated by an external handle 33. The liquid cryogen is supplied as needed through a combination of an air operated valve that is operated by a valve positioner 35 and a nozzle valve 34. An excellent valve 34 for this purpose is the shear orifice valve disclosed and claimed in the copending application of Ronald A. Banike Ser. No. 293,408, filed Sept. 29, 1972 and assigned to the same assignee as the present' application.

In order to show the internal fluid pressure in the valve 34 and thus to note when it is operating properly there is located a pressure gauge 36'on the cabinet wall I 37 that contains the insulation 26 for the blower 27.

The valve 34extends into the recirculation outlet 38 from the insulated blower 27 so as to supply the liquid cryogen at this outlet. The stream of liquid which in this embodiment is liquid carbon dioxide merges from the valve as indicated at 39 and is directed against a deflector 40 as shown in FIG. 7 which in this embodiment is at a 45 angle to the horizontal with the emerging stream 39 being at less than 45 to the horizontal and therefore less than tothe deflector 40.

The distribution system including the valve 34 and deflector 40 is the subject of a copending patent application of Ronald A. Banike Ser. No. 339,396, filed Mar. 8, 1973 now US. Pat. No. 3,818,719, and also assigned to the same assignee.

The valve 32 is connected to a relief valve 41 through tubing 42 and the valve 34 is connected to the pressure gauge 36 by tubing 43.

The deflector 40 greatly aids in distributing the fluid cryogen throughout the transverse width 44 of the freezing chamber or. tunnel ll uniformly and rapidly even when using'a single supply valve 34 as shown. Thus the combination of the single valve 34, the deflector 40 and the 90 turning vanes 45 that are located in a lid 13 as shown in FIG. 7 (described and claimed) in the present application rapidly and efficiently turn the fluid cryogen 39 from a generally transverse direction relative to the length of the tunnel 11 through 90 to a longitudinal direction toward the tunnel entrance 17. As seen in FIGS. 2, 6 and 7 the turning vanes 45 are positioned in an elevated lid 46 of the group of lids 13.

In order to refrigerate the articles on the conveyor 19 the fluid immediately contacts the articles which may be packages of food to be frozen, spaced meat patties and the like and the contact is by countercurrent flow as illustrated in the disclosed embodiment where the product being refrigerated flows from right to left or from the entrance 17 to the exit 18 as shown by the arrows 47 while the cryogen flows from left to right as indicated by the arrows 48.

Where the fluid cryogen is liquid carbon dioxide or the like at the point of introduction into the apparatus its passage through a flow valve such as the valve 34 immediately causes it to be converted into a mixture of solid snow and cold gas. The snow falls onto the tops of the articles and to a certain extent between the articles and is then itself converted into a cold gas. As is explained in the parent application the tunnel includes a final sublimation zone 49 between the cryogen introduction area 38 which coincides with the recirculation outlet 38 and the exit 18 from the tunnel. In this Zone 49 there are provided three spaced top mounted fans 50 each driven by an electric motor 51 and directed downwardly to insure sublimation of any solid carried by the articles on the conveyor 19 so that no solid particles are carried from the tunnel.

The cryogen introduction area 38 is spaced from the tunnel entrance l7 and there are provided means for withdrawing the spent cryogen gas at a withdrawal area 52 adjacent the entrance 17. This means comprises a horizontal cylinder 53 having a bottom opening 54 for receiving gas from the entrance 17 and a motor driven blower 55 exhausting the gas upwardly through an exhaust duct 56.

Located within the tunnel 11 adjacent to both the withdrawal area 52 and the conveyor 19 at the entrance 17 to the tunnel is an elongated flow confining baffle 57 that serves to increase the gas velocity in the area 58 beneath the baffle and above the conveyor 19 and the articles carried thereon. In one embodiment of the baffle 57 the bottom 59 was located about 1/2 inch above the tops of the articles carried by the conveyor which in this instance were flat ground meat patties.

The baffle 57 has the additional function of restricting or inhibiting the amount of spent cryogen gas 60 exhausted from the tunnel and also aids in regulating the proportion of the cryogen gas that is recirculated within the apparatus.

As is shown in FIG. 2 the tunnel beneath the conveyor 19 is provided with horizontal plates one of which 61 is located adjacent to the entrance 17 and the withdrawal area 52 and another of which 62 has one end spaced from the plate 61 and the other end extending beyond the cryogen introduction area 38 in the direction of the tunnel exit 18. The spacing of the adjacent ends of the plates 61 and 62 provides an entrance 63 to a bottom reach of a gas recirculation passage 64 that has one horizontal extent beneath the plate 62 and another horizontal extent above the plate 62 so that the gas is recirculated forwardly beneath the plate in the passage 64 and then downwardly in an insulated passage 65 (FIGS. 2 and 6), then horizontally as indicated at 66 and then upwardly as shown at 67 into the recirculation blower 27. From here the recirculated gas is exhausted by the blower horizontally through the area 38 where it is mixed with incoming fresh fluid cryogen 39 and turned from a transverse to a longitudinal direction as described by the 90 spaced turning vanes 45.

The passage areas 65, 66 and 67 comprise a transverse conduit loop from the bottom of the tunnel and back to the side thereof and into the tunnel by way of the turning vanes 45. In order to provide access to this loop the end of the horizontal passage 66 is provided with a removable plate 68 while the blower housing 78 itself is provided with a duct 69 normally covered by a removable plate 70 and with a bottom drain 79.

As stated earlier, the horizontal baffle 57 with sealed sides adjacent the entrance l7 contributes toward the gas balance between the exhaust 60, the recirculated gas 71 and the incoming fresh fluid cryogen 39 and further aided by top 80 and bottom 81 entrance baffles. In order to provide adjustment to this gas balance there is provided a thermally operated gas balance blade 72 of the type described in the parent application and a manually adjustable blade 73. The blade 72 is positioned within the tunnel 11 upstream or toward the entrance 17 from the cryogen introduction area 38 and is positioned to engage a stop 74 when in closed position or to the left of its position as shown in FIG. 2. The manual blade 73 as shown in FIGS. 2 and 6 is positioned at the top of the vertical passage 65 of the transverse gas bypass loop 75 that, as explained earlier, includes the passages 65, 66 and 67.

As is shown in FIGS. 2 and 4 the exit 18 is provided with a top exit curtain 77 that is in the form of individually suspended flexible strips. Immediately beneath this curt ain 77 is a downwardly hinged end plate 78.

In the description here the term cryogen is used in its broadest sense as defined in Websters New International Dictionary. The apparatus disclosed and claimed is usable with any liquid cryogen material but is particularly adapted for liquid carbon dioxide or the like which at atmospheric pressure exists as a solid snow and as a cryogen'gas. This snow which falls on the articles conveyed through the tunnel by the conveyor is sublime d primarily by heat transfer from the articles themselves during the refrigeration process. As explained earlier, as a further aid in this subliming the circulated atmosphere from the fans 50 adjacent the exit 18 of the tunnel is very effective.

The space 64 beneath the horizontal baffle 62 which is a part of the recirculation loop comprises a suction plenum chamber acted upon by the recirculation blower 27 to cause the recirculation of the cold gas. The manually adjustable damper blade 73 controls the entrance of the recirculated gas to the recirculation loop 75 (FIG. 6) and thereby controls the volume flow of recirculated gas. The thermally controlled damper blade 72 is operated by a motor 82 and also functions to control the recirculation flow. This damper blade and its control are described in the above parent application.

Having described my invention as related to the embodiment shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set outin the appended claims.

I claim:

1. Apparatus for refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen fluid from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; gas recirculation means comprising longitudinally extending baffle means between the top and bottom of said chamber and adjacent said articles path defining a recirculation path on opposite sides of said baffle means; means for withdrawing gas at a first area in said recirculation path from one side of said baffle means and reintroducing the gas at a second area in said recirculation path on the other side of said baffle means; an adjustable first flow control damper means at said first area; an adjustable second flow control damper means at said second area; and a transverse gas barrier in said chamber between said second area'and said exit from the chamber.

entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdrawal area and adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means 'to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from'said means for introducing toward said. chamber exit; and gas seal means at said recirculation passage portion on the side thereof adjacent said exit.

3. Apparatus for refrigerating articles, comprising:

means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining bafflemeans in said chamber between said introduction area and said withdrawal area and adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from said means for introducing toward said chamber exit; and gas seal means at said recirculation passage portion on the side thereof adjacent said exit, said gas seal means comprising a fixed seal member extending partially across said chamber and an adjustable seal means cooperating therewith for achieving a gas balance of the amount of gas in said recirculation passage. I

4. Apparatus for refrigerating articles, comprising: meansdefining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced-from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdrawal area and adjacent to said path for increasing gas velocity adjacent said conveyor'and restricting the withdrawal of said spent gas; means. defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means to said means for introducing the fluid cryogen with said recirculation passage including a por- I tion spaced from said means forintroducing toward said chamber exit, said means defining the recirculation passage comprising thermally insulated wall means; a thermally insulated blow'er means located in said thennally insulated wall means for forcing said gas through said recirculation passage; and gas seal means at said recirculation passage portion on the side thereof adjacent said-exit.

5. Apparatusvfor refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdrawal areaand adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said' baffle means to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from said means for introducing toward said chamber exit, said means defining the recirculation passage comprising thermally insulated wall means; a thermally insulated blower means located in said thermally insulated wall means for forcing said gas through said recirculation passage; and gas seal means at said recirculation passage portion on the side thereof therewith for achieving a gas balance of the amount of gas in said recirculation passage. 

1. Apparatus for refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen fluid from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; gas recirculation means comprising longitudinally extending baffle means between the top and bottom of said chamber and adjacent said articles path defining a recirculation path on opposite sides of said baffle means; means for withdrawing gas at a first area in said recirculation path from one side of said baffle means and reintroducing the gas at a second area in said recirculation path on the other side of said baffle means; an adjustable first flow control damper means at said first area; an adjustable second flow control damper means at said second area; and a transverse gas barrier in said chamber between said second area and said exit from the chamber.
 2. Apparatus for refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdRawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdrawal area and adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from said means for introducing toward said chamber exit; and gas seal means at said recirculation passage portion on the side thereof adjacent said exit.
 3. Apparatus for refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdrawal area and adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from said means for introducing toward said chamber exit; and gas seal means at said recirculation passage portion on the side thereof adjacent said exit, said gas seal means comprising a fixed seal member extending partially across said chamber and an adjustable seal means cooperating therewith for achieving a gas balance of the amount of gas in said recirculation passage.
 4. Apparatus for refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdrawal area and adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from said means for introducing toward said chamber exit, said means defining the recirculation passage comprising thermally insulated wall means; a thermally insulated blower means located in said thermally insulated wall means for forcing said gas through said recirculation passage; and gas seal means at said recirculation passage portion on the side thereof adjacent said exit.
 5. Apparatus for refrigerating articles, comprising: means defining a chamber having an entrance and an exit; conveyor means for moving said articles in the chamber in a path from the entrance to the exit; means for introducing a fluid cryogen into said chamber including a cryogen gas for contact with said articles at an introduction area of the chamber spaced from said entrance; means for withdrawing spent cryogen gas from said chamber at a withdrawal area of the chamber that is closer to the entrance than is said introduction area; a flow confining baffle means in said chamber between said introduction area and said withdRawal area and adjacent to said path for increasing gas velocity adjacent said conveyor and restricting the withdrawal of said spent gas; means defining a gas recirculation passage from adjacent to but short of the inner end of said baffle means to said means for introducing the fluid cryogen with said recirculation passage including a portion spaced from said means for introducing toward said chamber exit, said means defining the recirculation passage comprising thermally insulated wall means; a thermally insulated blower means located in said thermally insulated wall means for forcing said gas through said recirculation passage; and gas seal means at said recirculation passage portion on the side thereof adjacent said exit, said gas seal means comprising a fixed seal member extending partially across said chamber and an adjustable seal means cooperating therewith for achieving a gas balance of the amount of gas in said recirculation passage. 